1. Field of the Invention
The present invention relates to the field of medical devices and, in particular, to devices for delivery of fluid medicament(s). More particularly, the present invention relates to a multi-ported drug delivery device having a cartridge system with multiple interconnected reservoirs that are independently actuated for delivery of medicament(s), and methods therefor.
2. Description of the Related Art
Diabetes is a disease caused by the body's failure to produce adequate insulin or the cell's failure to respond to insulin resulting in high levels of sugar in the blood. Type I diabetes is a form of diabetes mellitus that results from autoimmune destruction of insulin-producing beta cells of the pancreas. There is no cure for Type I diabetes and must be treated on a continuing basis. Type II diabetes is a metabolic disorder resulting from a combination of lifestyle, diet, obesity and genetic factors. The World Health Organization recently predicted that by 2030, 10% of the world's population of all ages would have either Type I or Type II diabetes. This translates to roughly 552 million people worldwide suffering from some form of this disease.
If left untreated, diabetes can cause numerous complications. Typically, treatment for diabetes required both repeated checking of blood glucose levels and several injections of insulin throughout the day. Major drawbacks of such treatment were the need to draw blood and test glucose levels throughout the day, improper or low dosage amounts of insulin, contamination of the insulin delivery system, or lifestyle restriction.
Diabetes may be controlled by insulin replacement therapy in which insulin is delivered to the diabetic person, usually by injection, to counteract elevated blood glucose levels. Recent therapies include the basal/bolus method of treatment in which basal, a long acting insulin medication, for example, Humalog® and Apidra®, is delivered via injection once every day. The basal provides the body with a relatively constant dose or a dosage profile prescribed by the physician of insulin throughout the day. At mealtime, an additional dose of insulin, or bolus, is administered based on the amount of carbohydrate and protein in the meal. Accurate calculations of various parameters including the amount of carbohydrates and proteins consumed, and the lapse in time since the last dosage are necessary to determine the appropriate dosage of insulin. The dosages are thus prone to human error and the method is ineffective when doses are skipped, forgotten or miscalculated. Exercise, stress and other factors may also affect the bolus calculations to be inaccurate.
To address these problems, insulin delivery devices or insulin pumps—both manual and programmable—were developed which seek to mimic the way a normal, healthy pancreas delivers insulin to the body. Insulin pumps can be programmed to deliver a continual basal dose of insulin and occasionally a bolus dose in response to a patient's meal intake and physical activities. Additionally, the number of times a patient is required to draw blood and test their glucose during the day is reduced, thus lessening the pain and inconvenience of this disease. Also, micro-doses of insulin that can be delivered by programmable insulin delivery devices are more easily tolerated and rapidly metabolized by the body and thus, more effective.
Exemplary delivery devices are described, for example, in U.S. Pat. Nos. 3,137,242; 3,498,228; 3,771,694; 4,340,048; 4,544,369; 4,552,561; 4,498,843; 4,657,486; and 5,858,001 and U.S. Publication No. 2010/0081993 A1. These delivery devices have numerous disadvantages including but not limited to—their overall size, propensity for leakage, high costs that made them unaffordable for long-term disease management or unavailable for most patients, potential risks of over or under dosage due to the pumping mechanism, and delivery of medication in quick bursts rather than diffused over time.
The second generation of delivery devices or pumps mainly featured activation by means of a piezoelectric actuator. Such pumps are described, for example, in U.S. Publication No. 2004/0176727. These pumps have several known disadvantages such as alignment issues related to the piezoelectric actuator, power and voltage requirements, overall design of the pump being limited by the shape of the piezoelectric actuator, and a single reservoir design.
Conventional insulin pumps are worn on the body and are connected to a patient via a cannula that is inserted somewhere on the patient's abdomen. The insulin is delivered under the skin and is absorbed into the body through the subcutaneous fat layer. Subcutaneous delivery of insulin takes advantage of the lack of blood flow in this area that allows for slower absorption of the medication through the dermal capillaries. Other methods of non-invasive insulin delivery are described in Various Non-Injectable Delivery Systems for the Treatment of Diabetes Mellitus, Yadav, N., et al., Endocrine, Metabolic& Immune Disorders-Drug Targets, 2009, Vol. 9(1):1-13. Because the pump is worn on the user's body at all times, and users desire to conceal it by clothing, these pumps should be small and unobtrusive. Further, the tubing connecting the pump to the user must be relatively short to reduce crystallization of the insulin medication.
Insulin pumps in the past have been quite large, some requiring the use of a shoulder bag to transport. Over time, they have become smaller in size and most pumps today are roughly the size of a deck of cards. Currently available insulin pumps include Animas OneTouch® Ping®, Deltec Cozmo®, Disetronic Accu-Chek Spirit®, Insulet OmniPod, Medtronic Paradigm™, Sooil USA Diabecare® II, and Nipro Amigo®. One recurring problem with most miniaturized ambulatory infusion pumps available today is that the amount of medication that can be stored in the reservoirs often cannot meet the needs of certain diabetic patients. Many Type II diabetics who require insulin often need more insulin per gram of carbohydrate due to a condition referred to as “insulin resistance.” Additionally, many diabetic therapies include one or more medications delivered alternately or simultaneously. For this reason, a need exists for a delivery device that employs a plurality of reservoirs able to dispense medication at variable rates while maintaining a small overall size.
With the decreased size of the pump unit also comes a decreased size in the medication reservoir. This reduced reservoir size means more frequent refilling, greater potential for contamination of the reservoir, more frequent changes of the cannula and tubing, and greater expense overall in treating the condition. Frequent manual refilling of a medication reservoir can lead to an increased number of bubbles within the reservoir, which is a significant problem. Even very small bubbles, for example, of 10 microliters or less can displace enough fluid to equal a missed dose of 1 unit of medicament. Insulin medication itself can form bubbles when dissolved air is “outgassed” through normal changes in temperature or atmospheric pressure. Sooil USA Diabecare® II, Medtronic Paradigm™, Deltec Cozmo®, and Disetronic Accu-Chek Spirit® all require manual filling of the reservoir. The present invention overcomes the disadvantages of the existing systems by utilizing a volume that can exceed 300 u dual collapsible reservoirs prefilled with medicaments, with an option to redesign or re-conform the reservoirs to accommodate larger volumes.
Recent medical data suggests that a combination of insulin and another medication, such as glucagon, infused at different times or simultaneously, leads to better results in patients. Delivery of multiple medications is described, for example, in U.S. Publication Nos. 2007/0073230 A1; and 2011/0137287 A1. An advantage of the dual reservoirs of the present invention is that they can be manufactured to contain two dissimilar medicaments within the same disposable cartridge system, for instance, insulin in one reservoir and a different medicament in a second reservoir.
Finally, therapeutic infusion of medicaments is the prescribed treatment protocol for a variety of other diseases such as rheumatoid arthritis, autoimmune diseases, cancer, back and neck pain, joints, for the treatment of chronic pain, treatment of disc degenerative diseases, chemotherapy and tumor treatments. In the case of rheumatoid arthritis, the infusion therapy is usually administered over the course of several hours in a physician's office or infusion center and once or twice per month. This is a great inconvenience and expense for the patient that could be minimized by the use of an ambulatory infusion pump. The patient could be instructed on the procedure to self-administer the medication, insert a pre-filled medication reservoir at home and go about their normal daily routine. It has been shown that a lower dose of rheumatoid arthritis medication infused over a longer period of time produced better results with far fewer side effects.
Ambulatory infusion pumps that dispense a plurality of medications typically employ the use of multiple cannula, one cannula for each different medication and such pumps are described, for example, in U.S. Publication No. 2011/0137287 A1. The disadvantage of using a dual cannula is that there is a greater risk for infection and the problem with a y-shaped cannula is the awkwardness of the shape. Therefore, the need exists for an infusion pump that can deliver multiple medications from a plurality of reservoirs utilizing a multilumen infusion type cannula.